METHOD OF ESTIMATING DC-LINK CAPACITANCE OF CONVERTER ASSEMBLY AND CONVERTER ASSEMBLY

摘要

A method of estimating DC-link capacitance of a converter assembly, the converter assembly comprising a converter (EC) adapted to convert electric energy from one form to another, the converter (EC) has a first power connection (T1) which is a direct current connection, and a second power connection (T2), and a DC-link capacitor (C1) operationally connected to the first power connection (T1) of the converter (EC). The method comprises determining an initial voltage (u_{C1_t0}) of the DC-link capacitor (C1), effecting a voltage change of the DC-link capacitor (C1) in order to alter charge of the DC-link capacitor (C1), determining a final voltage (u_{C1_t1}) of the DC-link capacitor (C1), and calculating a capacitance (C_C1) of the DC-link capacitor (C1) using the initial voltage (u_{C1_t0}) and final voltage (u_{C1_t1}) of the DC-link capacitor (C1) and energy transition required for the voltage change of the DC-link capacitor (C1).